Low voltage, high current switch



April 24, 1956 H. w. GRAYBILL LOW VOLTAGE, HIGH CURRENT SWITCH 6Sheets-Sheet 1 Filed Oct. 27, 1952 all April 24, 1956 H. w. GRAYBILL LOWVOLTAGE, HIGH CURRENT swI'rcH e Sheets-Sheet 2 Filed Oct. 27. 1952 so llIN VENjOR. flaw/20 66992941 o fmhdfi Q 3% April 24, 1956 H. w. GRAYBILL2,743,338

LOW VOLTAGE, HIGH CURRENT SWITCH Filed Oct. 27, 1952 e Sheets-Sheet 5 INVEN TOR. o 8 flaw/yep 1/- wya/u.

April 24, 1956 H. w. GRAYBILL LOW VOLTAGE, HIGH CURRENT SWITCH 6Sheets-Sheet 4 Filed Oct. 27. 1952 April 24, 1956 H. w. GRAYBILL2,743,338

LOW VOLTAGE, HIGH CURRENT SWITCH Filed Oct. 27. 1952 s Sheets-Sheet 5SOURCE LOAD oamkmR r 5M J 5 wry/616575 April 24, 1956 H. w. GRAYBILL LOWVOLTAGE, HIGH CURRENT SWITCH 6 Sheets-Sheet 6 Filed Oct. 2'7, 1952United States Patent 0 LOW VOLTAGE, HIGH CURRENT SWITCH Howard W.Graybill, Greensburg, Pa., assignor, by mesne assignments, to I-T-ECircuit Breaker Company, Philadelphia, Pin, a corporation ofPennsylvania Application October 27, 1952, Serial No. 317,101 14 Claims.(Cl. 200-164) My invention relates to a novel short circuit switch andmore particularly to a short circuit switch which lends itself to aflexible assembly into any desired combination such as for a single ormultipole operation or operation in large units through a commonoperating handle.

In electrolytic process operations, the voltage across a cell iscomparatively low, generally on the order of three to six volts. Sincethe output of the cell is directly proportional to the operatingcurrent, cells are usually designed for operation at high currents,usually in the range of 10,000 to 60,000 amperes. Hence, economicconsiderations dictate that individual cells be connected in seriesrather than in parallel.

With this type of electrolytic system, when one of the cells becomesdefective for any reason and must be removed for inspection and repair,it is, of course, undesirable to shut down the entire line. It would bepreferable to be able to remove the defective cell for inspection whilethe line is left otherwise intact for continuous operation.

The removal of such a unit may be achieved, as is well known in the art,by a switch inserted across the terminals of the defective pot cell tobe removed. Thus, providing the shunt circuit in the series system withthe switch that is connected across the cell, the latter can now bewithdrawn from the system.

Inasmuch, however, as the system carries large currents, the switchingdevice connected across the line must be able to carry these largecurrent values across the contacts without any excessive RI drop whichwould generate heat at the contacts of the switch.

The large current which must pass through the con tacts often makes itdesirable that a multiplicity of contacts be connected in parallel. Foreffective operation of a plurality of such contacts, provision must bemade for self-alignment to insure simultaneous engagement anddisengagement of the contacts.

Heretofore, short circuiting switches for pot line use were made withthe conducting members thereof resilient so as to achieve high contactpressure. That is, the conducting members, which are to carry currentloads as high as 60,000 amperes were constructed of or with resilientcomponents, in order to insure good contact engagement. However, due tothe fact that the conducting members were not rigid components,misalignment frequently occurred after prolonged use of the switches anddue to the fact that these units were designed to carry relatively highmagnitudes of current, the conducting surfaces were frequently burnedand corroded after prolonged usage.

With my novel invention, I propose to overcome all of the disadvantagesof the short circuiting switches of the prior art by:

1. Providing a structural arrangement in which all of the conductingmembers are rigid units and wherein (a) high contact pressure isobtained by biasing means independent of the conducting units and (b)structural con- 7 2,743,338 Patented Apr. 24, 1956 figuration permitsthe relatively small force of the biasing means to be resolved intorelatively high forces which are normal to stationary conductingsurfaces.

2. Providing a novel short circuiting switch wherein a plurality ofbridging movable contacts are of identical structure and providing aunique construction whereby one of the plurality of movable contactsacts as an arc ing contact member.

Moreover, since such a switch will only rarely be used, there may be atendency for corrosion at the contacts.

Accordingly, my invention contemplates a novel disconnect switch havingsilver to silver high pressure contacts, silver plated high conductivityhard copper, self aligning contacts and suitable terminal insulation.

Accordingly, an object of my invention is to provide a novel disconnectwhich is sufficiently flexible to permit its operation as a single ordouble-throw switch.

A further object of my invention is to provide a novel short circuitingswitch in which each opening and closing operation is achieved with awiping action.

A further object of my invention is to provide a novel disconnect inwhich high pressure contact engagement is secured over multipolecontacts in parallel.

Another object of my invention is to provide a multipole high pressureswitch in which self-alignment provides simultaneous contact engagement.

Another object of my invention is to provide a cell cutout disconnectswitch having a plurality of cooperating contacts which are controlledfrom a single control shaft to insure simultaneous operation.

A further object of my invention is a novel disconnect switchconstructed in a manner to increase the contact pressure just prior tofull contact engagement and disengagement to insure wiping action underhigh pressure.

Another object of my invention is to provide a multipole shortcircuiting switch in which all of the movable contacts engage and seatwith the stationary contacts individually and independently.

Another object of my invention is to provide a novel wedge shapedengagement between the conducting mem bers to thereby achieve linecontact engagement.

A still further object of my invention is to provide a novel contactengagement means whereby the biasing vertical force can be resolved intotwo normal components to achieve a relatively high contact pressure.

A still further object of my invention is to provide a novel disconnectswitch wherein all the conducting members thereof are rigid integralunits.

A still further object of my invention is to provide a high current lowvoltage switch in which the resilient means to provide high contactpressure engagement is independent of the conducting materials thereof.

A still further object of my invention is to provide a short circuitingswitch in which the mean length of the conducting path is relativelysmall to thereby reduce the millivolt or IR drop loss therein.

Still another object of my invention is to provide a novel switch inwhich the losses to the millivolt or IR drop are small.

Another object of my invention is to provide a novel circuitinterrupting means in which the plurality of bridging contact membersare uniform in construction and provide arcing and main contacts for theswitch.

Still another object of my invention is to provide a short circuitingswitch with a plurality of parallel bridging contact members wherein onecontact member is connected to efiect contact engagement anddisengagement before and after, respectively, and the engagement anddisengagement of its associated bridging contact members.

Another object of my invention is to provide a dis connecting means witharcing and stationary contacts without the necessity of specialconstruction for the contacts and wherein arcing and main contacts haveidentical construction.

V The structure and operation of the novel disconnect switch of myinvention will best be understood from the following description takenin connection with the drawings, in which:

Figure l is a perspective view of one embodiment of my novel disconnectswitch.

Figure 2 is a side view of the switch of Figure 1 showing the positionof the member just prior to final contact disengagement when theoperating shaft is rotated counterclockwise.

Figure 3 is a view of the switch of Figure 1 showing the position of themember when the contacts are in full disengaged position.

Figure 4 is a side view .of the disconnect switch of Figure 1 showingthe position of the members when the contacts are in full disengagedposition following clockwise rotation of the operating shaft.

Figure 5 is a perspective view of the bottom of the novel disconnectswitch of Figure 1.

Figure 6 is a perspective view of another embodiment of a noveldisconnect switch of my invention.

Figure 7 is an end view of the disconnect switch of Figure 6.

Figure 8 is a side view of the disconnect switch of Figure 6.

Figure 9 is a cross-section view of the switch unit of Figure .6 takenalong the line AA of Figure 8.

Figure 10 is a top view of the disconnect switch of Figure 6.

Figure ll is a schematic diagram illustrating the cir- Quit and mannerin which my novel switches can be connected in parallel for pot line orcell cutout application.

Figure 12 is a schematic wiring diagram illustrating how the novelswitches of my invention can be used as a single pole, double throwswitch. 7

Figure 13 is a schematic wiring diagram illustrating how the novelswitches of my invention can be used as a double pole, single throwswitch.

Figure 14 is a schematic wiring diagram illustrating how the novelswitches of my invention can be used as a double pole, double throwswitch.

Figure 15 is a perspective schematic view illustrating the manner inwhich the illustrated switches of Figures l1, l2, l3 and 14 can beinterconnected to function simultaneously.

Figure 16 is a side view of a modified switch of my invention showingthe bridging contact member in engagement with the stationary contactsand vectorially illustrates the increased contact pressure derived fromthe contact biasing spring.

Figure 17 is a perspective view of the modified switch of Figure 16showing the conducting units in disengaged position and illustrates theposition of the arcing contact with respect to the remaining bridgingcontacts.

Referring now to Figures 1, 2, 3, 4 and 5, the steel operating shaft 10is the main control of the semi-cylindrical bridging contacts 11. Theoperating shaft 10 is journaled in the bushings which arepresseddirectly into the side plates 14 and 1S. Collars 12 and 13, concentricwith the control shaft 10, are keyed thereto to prevent endwise motionof the shaft. The operating shaft 10 is provided with radial holes 21 toreceive the shaft 22 of operating handle 23. Hence, the operating shaft10 can be rotated clockwise and counterclockwise within the bearlugs ,12and 13 by either upward or downward movement of the operating handle 23.The outer circumference of the operating shaft 10 has a plurality of Ushaped stamped extension arms 16 rigidly secured to the operating shaft10 and the legs 18 and 19 protrude radially therefrom. Each of theplurality of legs 18 and 19 is provided with an elongated slot 20 whichextends radially from the operating shaft 10 and act as a support andguide for the pin 25. A pin '25 is transverse and integrally connectedto one end of each of the contact arms 26. The other end of the contactrod 26 has the semicylindrical bridging contact 11 secured thereto whichis preferably a silver surfaced copper block. Each contact rod 26 has aconcentric spiral compression spring 26 preferably made of stainlesssteel, which rests at each end against the washers 28 and 29. Thus, whenthe control shaft 10 is in the closed position .of Figure l, thecompression spring '27 will urge the bridging contact 11 downward intotight positive engagement.

The L shaped terminal connectors 30 and 31 are supported betweeninsulator blocks 32, 33, 34 and 35. The terminal connectors 30 and 31are rigidly secured to the channel or U shaped base plate by means of aplurality of bolts and nuts 41 and 42. The bolts 41 extend through thealigning insulators 33, 34 and 35, terminal members 30 and 31, insulatorblocks 32, 33 and 34, U shaped base plate 40 and are secured in place bynut 42 as seen in Figure 5. Insulating tubes are placed around the bolts41 to insulate. these members from terminal members 30 and 31 to insurethat no potential exists between adjaccnt bolts 41. One end of theterminal connectors 30 and 31 is provided with appropriate means 38 forelectrical connection to the circuit. The other end of the L shapedterminals 30 and 31 are milled at an angle of about 20 degrees from theperpendicular. These inclined surfaces of the copper terminals 30 and 31are silver surfaced and form the stationary contacts which are bridgedby the movable contacts 11.

The operation of the switch is as follows: when the movable bridgingcontact member 11, is in engagement with the stationary contacts and 51,the operating handle 23 is in the neutral or horizontal position, asseen in Figure 1. As manual upward pull on the operating handle 2.3 willrotate the operating shaft 10 in a counterclockwise direction. Duringthe first 25 degrees of rotation of the operating shaft 10, the movablebridging contact 11 will be rotated with respect to the stationarycontacts 50 and 51 thereby creating a wiping action between thecontacts. The rotational movement of the movable contact 11 is caused bythe relative movement between the pin 25 and the slot 20 of the leg 18.Hence, immediately prior to contact disengagement during openingoperation, and as will hereinafter be apparent, immediately prior tocontact engagement during the closing operation, there is a highpressure wiping action to remove any dirt or corrosion, from thestationary contact surfaces. That is, the contact compression spring 27is compressed during the rotational movement between Figures 1 and 2 toinsure high pressure wiping action.

After approximately 25 degree rotation of the operating shaft 10, thecontacts will be in the position of Figure 2. As noted, the pin 25 ofthe contact rod 26 wit? now be at the lower end of the elongated slot 20and the movable contact 11 will still be in engagement with at least aportion of the stationary contacts 50 and 51. However, with furtherrotation of the operaitng shaft 1t), relative movement between the pin25 and the slot 20 is no longer possible since the pin 25 is now restingagainst the bottom of the slot 20. Hence, further rotation of theoperating shaft 10 from the position of Figure 2 to the position ofFigure 3 will withdraw the movable bridging contact 11 along a straightline to the position of Fig-- ure 3. That is, continued rotation of theoperating shaft will lift contact member 11 up and out of engagementwith the stationary contacts 50 and 51 of terminal members 3i] and 31.In this position, the contacts 11, 50 and 51 will be disengaged and thecircuit will be interrupted. Although the contact 11 is disengaged fromboth the stationary contacts 50 and 51, a larger air gap will occurbetween contacts 11 and 50 than between 11 and 51, as best seen inFigure 3. It will be noted that this type of switch is used for highcurrent low voltage application and hence, since very little voltagewill occur between the contacts, the separation distance need not bevery large.

It will be further noted that the switch can be opened by eitherclockwise or counter-clockwise rotation of the operating shaft 10.Figures 2 and 3 show the relative position and operation of thedisconnect switch when the handle 23 rotates the operating shaft 10 inthe counterclockwise position for opening. Figure 4 illustrates therelative position of the parts when the operating shaft is moved fromthe position of Figure 1 in a clockwise direction by means of operatinghandle 23. The manner and function of this operation is the same as thatnoted for counterclockwise rotation and differs only by having thelarger air gap appear between contact 14 and stationary contact 51rather than stationary contact 50.

It will be noted that the plurality of contact structures a, b, c and dare identical in construction and hence, the single rotation ofoperating shaft 10 will have the same efiect 011 all the bridgingmembers 11. By this manner, simultaneous operation of the members ispossible to insure that each parallel path is simultaneously broken.

The action of the switch for closing operation is the reverse of thatdescribed for the opening operation. That is, the handle 23 is movedclockwise from the position of Figure 3 and the movable member is movedthrough the position of Figure 2 to the position of Figure 1. Thus, theoperating handle 23 will again be in its neutral or horizontal position.

As the movable contact 11 is moved from the position of Figure 3 to theposition of Figure 2, it will move downward in a straight line to theleft. Hence, if prior to its rotational movement from that of Figure 2to Figure l, the movable contact 11 will engage the insulating block 33,the member 33 will there act as a guide or aligning unit to insure thatthe semi-cylindrical bridging member 11 will rotate into properengagement with stationary contacts 50 and 51. Hence, rotation of theoperating shaft 10 closes the switch unit by engaging the fourself-aligning bridging contacts 11 directly between the stationarycontacts 50 and 51 of terminal members 30 and 31.

When the switch unit is in the engaged or closed position, the currentflow will be through terminal connector 31 (from the electricalconnection at 38 which is not shown), through stationary contact tdivided into four equal parallel paths through bridging contact 11,through stationary contact 50, terminal connector 30 and to the line(not shown) connected at 38.

Thus, in summary, I have provided a novel short circuiting switchwherein the main current conducting members 30-50, 11 and 31-51 are allrigid integral units with high contact pressure being supplied frombiasing means 27 which is independent of the current conducting members.Hence, due to the fact that all of the conducting units are rigidmembers, the high current low voltage switch is a rugged device whichwill not misalign after repeated usage.

As heretofore mentioned, the prior art short circuiting switchesrequired that that conducting members have re silient properties inorder to achieve high contact pressure and thus, frequently misalignedafter extensive use.

By providing independent biasing means, such as compression spring 27,it is possible to have a short current path of heavy cross-section,since deflection of conducting members is not required.

Furthermore. by providing a unique arrangement in which the biasingmeans 27 is individual and independent to each of the bridging contacts11, the plurality of movable contacts are able to seat themselvesindividually and independently during contact engagement. That is, thefinal seating of the movable contact 11 within the wedge shapedstationary contacts 50 and 51 permits the compression spring 27 toadjust and seat its associated movable 6 contact 11 therebetweenirrespective of the position of the remaining movable contacts.

It is further noted that with my unique switch, contact engagement, asthe switch moves from the position of Figure 3 through the position ofFigure 2 to the position of Figure l, is achieved primarily by theaction of the compression spring 27. That is, as the operating shaft 10is rotated from the position of Figure 3 to the position of Figure 2,the contact bar 27 is moved downwardly and in the position of Figure 2the cam 18 urges the washer 33 downwardly to compress the contact spring27. Hence, the compressed spring 27 represents the link between theoperating shaft 10 and the bridging contact 11 to urge the latter memberfrom the position of Figure 2 to the position of Figure 1.

Since this latter motion is achieved while the contact spring 27 isunder compression, the wiping action occurs under high pressure. Incontra-distinction, the disengagement of the contacts from the positionof Figure 1 through the position of Figure 2 to the position of Figure 3is achieved through the linkage mechanism of the cam 18 and the contactrod 26.

That is, the contact disengagement is caused by the action of the cam 18on the contact rod 26 and occurs without benefit of the energy of thebiasing means 27. Hence, contact disengagement or the pulling away ofthe movable contact 11 from the stationary contacts 50-51 is achieved bythe positive linkage of 11, 26, 25, 18, 10 independently of the spring27 whereas contact engagement is made at the benefit of the force frombiasing spring 27, as above noted.

A modification of the novel switch shown in Figures 1 through 6 is shownin Figures 16 and 17. The modified switch of Figures 16 and 17 differsin the following respects:

(1) A unique construction for the assembled movable contacts permits oneof these contacts to engage and disengage the stationary contacts beforeand after, respectively, the other movable contacts engaging anddisengaging the movable contacts. This construction enables one of themoving contacts to act as an arcing contact to thereby insure that nopitting or burning will occur at the other movable contacts.

(2) The moving contact lever is made with a hair pin construction toreplace the contact rod 26. That is, in the embodiment of Figures 1through 6, it was necessary to provide an elongated slot in the rod 26in order to insure that each of the movable contacts seated individuallyand independently. However, with the unique hair pin construction of themoving contact lever, as shown in Figures 16 and 17, the necessity ofproviding an additional elongated slot, entailing increasedmanufacturing difficulties and expense, is eliminated.

(3) A blocking insulator 35, as seen in Figures 1 through 6, is replacedby a channel shaped conducting member which (a) due to its heatconducting properties, conducts excess heat away from the contactengaging surfaces, (b) permits freer circulation of air around thecontact engaging surfaces. and (0) provides a plurality of radiatingfins to dissipate the heat conducted therein into the air by means ofradiation.

As best seen in Figures 16 and 17, operating shaft 10 is provided with aplurality of integrally attached U- shaped members 201. The movablecontact member 110, identical in construction to the movable contactmembers 11, as seen in Figures 1 through 6, is provided with an U-shaped moving contact lever 202.

The hair pin 202 is permanently secured to the bridging contact member11a by means of screws 203, 204 inserted through the feet 205-406 of thehair pin member 202.

The movable contact assembly, comprising a movable contact lla and ahair pin member 202, is rotatably mounted to the U-shaped cam 201 bymeans of the pin 208 which is positioned in the channel formed by theplurality of members 201-202.

The bus terminal connectors and 31 are identical in construction to thebus terminal members of the embodiment of Figures 1 through 6 and areprovided with beveled edges -51 forming wedge shaped stationarycontacts.

Channel members 210-211 are secured to the upper surface of the busterminal members 30-31 by means of bolt and nut arrangements 212-213.The bolts 212- 213 are provided with insulating sleeves 215-216 andserve to connect the insulators 218-219-220-221 to the bottom surface ofthe bus terminals 30-31.

In the embodiment of Figures 1 through 6, the insulating members 33-35are positioned on top of bus terminals 30-31 to serve as guides for themovable contact members 11. However, in the modified embodiment ofFigures 16 and 17, these insulating members are replaced by the channelunits 210-211. The flanges 225- 226 of these units serve as guides toinsure proper seating of the movable contact member 11 into the wedgeshaped stationary contacts 50-51.

The channel shaped members 210-211 are also provided with flanges 227and 228, which, along with flanges 225 and 226, serve to radiate theexcess heat which is conducted through the members 210 and 211 from theconducting area at 50-11a and 51-11a. It will be further noted that byproviding channel shaped members 210 and 211, greater circulation of airis permitted around the conducting surfaces to thereby enable the heatto be more readily dissipated.

Asbest seen in Figure 14, a vectoral diagram is superimposed on the endview of the short circuiting switch. It will be noted that thedistribution of forces, as herein more fully explained, applies to boththe embodiment of Figures 1 through 6 and the modified embodiment ofFigures 16 and 17. It will be further noted that the magni tude of thevarious vectoral components indicated is merely illustrative as toproportions of the forces and may be varied within wide limits forpractical and com mercial applications.

As heretofore noted, the beveled edges 50-51 of the bus terminals 30-31,forming wedge shaped stationary contacts into which the semi-cylindricalmovable contact 11a is seated when the contacts are in engaged position.Hence, a point or a line contact is made between conducting members 11and 30-31 at the points 230-231 to thereby enable all of the availableforce to be concentrated in a relatively small area to thereby increasethe contact pressure.

The seven pound downwardly extending vertical force is representative ofthe force exerted on the movable contact 11a from the contactcompression spring 27.

As will hereinafter be apparent, with my novel wedge shaped engagementof the conducting surface, the downwardly extending vertical force fromthe spring 27 is resolved into components which act normal to thestationary contacts 50-51 and have a magnitude greatly in excess of thevertical force to thereby obtain high contact pressure.

The seven pound downwardly extending vertical force may be vectorallyillustrated by the two 3.5 lb. downwardly extending vertical forces atpoints 230-231. This downwardly extending force of 3.5 lbs. whenresolved into its components, results in a horizontal force of 9.6 lbs.and a normal force to the surfaces 50-51 of 10.2 lbs. as indicated.

Hence, contact pressure between the movable contact 11a and thestationary contacts at 50-51 will be of the magnitude of 10.2 lbs. atthe line engagement 230-231. That is, with my novel arrangement, arelatively small downwardly extending vertical force of seven poundsfrom the compression spring 27 may be resolved into components whichenable a 10.2 lb. force to be exerted at the point of contactengagement.

As'above noted, a modified embodiment of Figures I6 arid r7 prdvidesahovelstructttral arrangement for short ircuiting switch wherein an themovable contacts are of identical construction and so arranged that oneof the plurality of bridging members serves as an arcing contact tothei'cby'rclleve'tlieremaining conducting members from the burden ofinterrupting the circuit.

Referring now to Figures 16 and 17, the plurality of movable contacts11a, 11b, 11d, 11e have the hair pin member 202 directly connected tothe upper flat surface thereof. Hence, these four movable contactmembers, which are designed with sutficient cross-sectional area tocarry the full load to be shorted or opened by the high current lowvoltage switch, are in substantially the same horizontal plane and will,therefore, engage and disengage the stationary contacts 50-51 atsubstantially the same time.

The center movable contact 110, as best seen in Figure 17, is providedwith a washer 250 which is seated below the feet 205-206 of the hair pin202 and the bridging contact 110.

it will be noted that with the exception of additional washer means 250,the entire movable contact assembly consisting of movable contact 11a,hair pin member 202 and compression spring 27 are identical inconstruction to the remaining movable contact structures 11a, 11b, 11dand 11a. However, the insertion of the additional washer means 250permits the center movable contact structure 11( to be seated lower thanthe remaining four units.

Hence, when the operating shaft 10 is rotated to effect contactengagement, the movable contact 11c will engage the stationary contactbefore the remaining movable contacts 11a, 11b, 11d, 11e are broughtinto engagement.

It will be noted that after the contacts are in full engaged position,as seen in Figure l6, they are all seated on the same horizontal plane.That is, even though the center contact 11c is provided with additionalwasher means 250, stationary contacts 50-51 prevent it from movingfurther down than the remaining bridging contacts 11 a, b, d and e.

Thus, the contact spring 27 associated with the contact structure of1.10 will be compressed to a greater extent than the remaining contactsprings to enable its associated movable contact to seat itself withinthe wedge shaped stationary contacts in the same plane as the remainingmovable contacts.

Thus, due to the fact that the compression spring 27 of the movablecontact assembly 11c is compressed to a greater extent than theremaining compression contact springs, the wiping action of this arcingcontact will occur under greater pressure than the remaining structuresto thereby more readily remove the excess pitting which occurs oncontact structure 110, as above noted.

In like manne, due to the fact that the washer means 250 permits themovable contact structure to be seated below the remaining contacts,contact structure 110 will be the last unit to disengage from thestationary contacts. That is, when the operating shaft 10 is rotated toeffect contact disengagement, the plurality of movable contacts 11a.11b, 11d and lie will disengage the stationary contacts before thecenter contact structure 110 disengages same. Hence, the entire burdenof arcing and resulting pitting of contact surface will occur on the onemovable contact structure, namely 110 so that it acts in substantiallythe same manner as an arcing contact, as is well known in the art.

By this novel arrangement, I am able to provide a short circuitingswitch in which the plurality of movable contacts are designed to havesufiicient cross-sectional area to carry the full load requirements ofthe switch and in which the added identical contact structure isprovided to carry the interrupting burden and the switch. Thus, by thisarrangement, only contact 11c will become pitted or burned threw theinterrupting dutiesthus preserving the conducting surfaces of theremaining bridging members 11a, 11b, 11d and He.

Another embodiment of my invention is illustrated in Figures 6, 7, 8, 9and 10. In this embodiment, the position of the bridging movable contactis also controlled by the rotation of a control shaft. However, thebridging member is a flat conducting member rather than asemicylindrical unit and follows only vertical linear movement ratherthan rotational and linear movement.

The main operating shaft 60 is journalled in the bearing members 61 and62 which are mounted on support members 63 and 64. The support members63 and 64 are in turn rigidly secured to U shaped base plate 66,comprising legs 67 and 68 and base 69 by means of bolts 75. The baseplate 66 is made of a suitable electrical insulating material, such asphenolic plastic. A pair of col lars 120 and 121 are secured to theoperating shaft 60 adjacent to the bearings 61 and 62. By means ofcollars 120 and 121, longitudinal movement of the shaft 60 is restrictedand its movement is thereby limited to rotation. The operating shaft 60has a plurality of cam members 76 and 77 rigidly attached to its outerperipheral surface. The cam members 76 and 77 engage the longitudinalbar 78. The longitudinal bar 78 has protrusions 79 and 80 at each endlocated above the extensions 85 and 86 on legs 67 and 68 of base support66.

Compression springs 90 and 91 are seated between protrusions 79 and 80and extensions 85 and 86 to bias the longitudinal bar 78 upward. Thelongitudinal bar 78 is seated above the extension 85 and between thelegs 67-67 and 68-68 of U-shaped base plate 66. Hence, the positioningof bar 78 in the cutout of legs 67 and 68 will insure that the bar 78has no transverse movement and the end supports 63 will limit thelongitudinal movement of this unit. Thus, the longitudinal bar 78 willbe limited to vertical movement.

A plurality of H-shaped leaf springs 92 and 93 are secured to thelongitudinal bar 78 by means of screws 95. Each leg of the H-shaped leafsprings 92 and 93 is attached to a copper bridging contact 98 by meansof attaching screws 100 and 101. Silver contacts 102 and 103 are weldedto each end of each of the plurality of bridging contacts 98. When theassembly comprising the longitudinal bar 78 and bridging contact 98 ismoved downward by action of the operating shaft U shaped cam 76, thesilver contacts 102 and 103 will engage the stationary contacts 105 and106. The plurality of stationary contacts 105 and 106 are secured to Lshaped terminal connectors 107 and 108. The L shaped terminal connectors107 and 108 are secured to the bottom side 69 of the U shaped base plate66 by means of bolts and nuts 110 and 111. The switch unit is connectedin an electrical circuit by making appropriate connections at 112 and113 on terminals 107 and 108, respectively. When the switch is in theengaged or operating position of Figure 6, the flow of current is fromthe line to the terminal connector 107 by means of connection at 112,through the plurality of stationary contacts 105 to the four parallelpaths of movable contact 102, copper bridging member 98, movable contact103, stationary contact 106, through terminal connector 108 and then tothe electrical circuit connected thereto at 113.

The operation of the switch unit is as follows. When the switch is inthe open position, as shown in Figures 7, 8, 9 and 10, the bridgingmember 98 and its associated movable contacts 102 and 103 are biased tothe disengaged position by means of compression springs 90 and 91. Inorder to bring the contacts into engaged position, the operator rotatesthe operating shaft 60 in either a clockwise or counterclockwiseposition. Initial rotation of the operating shaft 60 will rotate theintegrally attached cam member 76 into engagement with the longitudinalbar 78. Continued rotation of the operating shaft 60 will depress thelongitudinal bar 76 against the bias of compression springs 90 and 91.When the movable contacts 102 and 103 engage stationary contacts .105and 106, respectively, continued downward movement of thebar 78 by thecam 76 will cause the leaf springs to deflect. In the final engagedposition, as seen in Figure 6, the bottom leg 76' is seated on top ofthe longitudinal bar 78 to prevent accidental opening due to shock orvibration. I n this position, contacts 102 and 105, 103 and 106 are inengagement and hold in tight contact due to the resilience of leafsprings 92 and 93.

Action of the switch for opening is the reverse of that described forclosing. That is, the operating shaft 60 can be manually rotated ineither a clockwise or counterclockwise direction to thereby remove thecam 76 from engagement with longitudinal bar 78. This action will permitthe compression springs and 91 to move the bar 78 and associatedbridging member 98 upward to thereby effect contact disengagementbetween 102 and 105, and 103 and 106.

The switch of my invention including the embodiment of Figure l andFigure 6 is primarily a low voltage high current device for potline orcell cutout application. For example, in cases where a plurality ofcells a, b are connected in series across a source 111, it isundesirable to close down the entire network in the event that one cellbecomes defective or needs replacing. Hence, for example if cell 10ashould require replacing, a plurality of disconnect switches 112 wouldbe connected in shunt with the defective cell. The plurality of switches112 can be operated from a single operating shaft 60 to simultaneouslyclose all the contacts 11, 50, 51 and thereby short out the cell 110a sothat it may be repaired or replaced.

It will be further noted that the switches of my invention can bearranged so that a plurality of switches can be operated from a singleshaft as seen in Figures 11 and 15. Furthermore, the switch of myinvention can be used as either a single pole double throw, double polesingle throw, or double pole double throw switch.

Figure 12 illustrates the arrangement and connection for the switches asa single pole double throw unit oper-- ated from a single control shaft60. For this arrange ment, one switch unit (a) is in the closed positionwhen the other switch unit is in the open position for a particularposition of the operating shaft 60. For double polefsingle throwoperation, as seen in Figure 13, both switch units a and b aresimultaneously in open or closed position.

For double pole double throw application, as seen in Figure 14, fourswitch units a, b, c and d are required to be connected and arranged sothat the pair of switch units a and b are open when the pair of switchunits: 0 and d are closed. Hence, when the shaft 60 is rotated to closethe switch units a and b, the left load will be connected to the source.When the operating shaft 60 is rotated to open units a and b and closeswitch units 0 and d, the right load will be connected to the source.For double pole applications, an insulating section is inserted in theconnection between shafts of opposite polarity.

In the foregoing, I have described my invention only in connection withpreferred specific embodiments and applications thereof. Many variationsand modifications of the principles of my invention within the scope ofthe description herein are obvious. Accordingly, I prefer to be boundnot by the specific disclosure herein but only by the appending claims.

I claim:

1. In a disconnecting switch having a plurality of movable contacts anda pair of stationary contacts having a wedge shaped gap therebetween,means for simultaneously operating said plurality of movable contactsinto said wedge shaped gap for engagement with said pair of stationarycontacts; a guide member engaged by said plurality of movable contactsprior to their engagement with said pair of stationary contacts forautomatically align- 11 ing said plurality of movable contacts prior totheir engagement with said pair of stationary contacts to providesimultaneous contact engagement of said plurality of movable contactswith said pair of stationary contacts.

2. A circuit interrupter comprising relatively movable contacts, apivoted toggle member to open and close said contacts, operatingmechanism comprising a pivoted operator manually movable to effectopening and closing movement of said contacts, said toggle member beingpivotally connected to said manual operator, one of said contactsconnected to one link of said pivoted toggle, a compression springlocated between said contact and the knee of said toggle to bias saidcontact into electrical engagement with a stationary contact.

3. In a circuit interrupter comprising a cooperating electricalcontacts, having a movable contact to bridge two stationary contactswhen in closed position, rotational means to manually position saidmovable contact with respect to said stationary contact, said rotationalmeans imparting rotational and linear movement to said movable contactto insure wiping action and relative contact movement, said linearmovement imparted to said movable contact by said rotational means beingin a direction perpendicular to the plane of said stationary contacts.

4. In a disconnect switch comprising a plurality of cooperating contactsfor completing and interrupting an electrical circuit between a pair ofbus bar terminals, operating means rotatably supported on a switchsupport frame comprising a shaft with a plurality of integrallyconnected U shaped flanges protruding therefrom, each leg of said Ushaped flanges having a receiving slot, a plurality of actuated armseach having a transverse pin integrally connected at one end thereof anda semi-cylindrical movable contact integrally connected at the other endthereof, said actuated rod slidably secured to said U shaped flanges byengagement of said pins with said re ceiving slots. a biasingcompression spring concentric with each of said actuating arms seated atone end on a fiat surface of said semi-cylindrical movable contact andseated at the other end on the legs of said U shaped flanges. said Ushaped flange and said actuating arm being in axial alignment with saidmovable contact is in engagement with the stationary contacts of saidbus bar terminals, rotation of said operating means elfective to wipesaid movable contact against said stationary contacts and to move saidmovable contact out of engagement with said stationary contact.

5. In a disconnect switch having stationary contacts engageable bymovable contacts comprising a control shaft, biasing means and washers;said control shaft having a plurality of cams integrally attachedthereto, said control shaft connected to said movable contacts byengagement of said cams with said washers to control the operation ofsaid movable contacts through said biasing means.

6. In a disconnect switch having stationary contacts engageable bymovable contacts comprising a control shaft, biasing means and washers;said control shaft having a plurality of cams integrally attachedthereto, said control shaft connected to said movable contacts byongagement of said cams with said washers to control the operation ofsaid movable contacts through said biasing means, said biasing meansoperatively connected to insure contact pressure during contactengagement, said movable contact having a moving contact leverintegrally attached thereto, said control shaft connected to effectcontact disengagement through said cams and "said moving contact leverindependent of said biasing means.

7. A short circuiting switch comprising ajpair of cooperating contactsfor opening and closing an electrical circuit, said cooperating contactscomprising asemi-cylindrical movable contact and a pair of bus terminalshaving beveled edges forming stationary contacts, said beveled surfacesof said pair of bus terminals forming a wedge shape to receive saidsemi-cylindrical bridging contact, said bridging contact makingtangential line contact with said beveled edges, said Wedge shapeengagement of said movable contact with said stationary contactspermitting a relatively small vertical force to be resolved into tworelatively high normal forces to said beveled surfaces to therebyachieve high contact pressure, said semi-cylindrical movable contacthaving rotational and linear movement with respect to said pair of busterminals, said linear movement of said semi-cylindrical movablecontacts being perpendicular to the plane of said bus terminals.

8. A short circuiting switch comprising a pair of cooperating contactsfor opening and closing an electrical circuit, said cooperating contactscomprising a semi-cylindrical movable contact and a pair of busterminals having beveled edges forming stationary contacts, said beveledsurfaces of said pair of bus terminals forming a wedge shape to receivesaid semi-cylindrical bridging contact, said bridging contact makingtangential line contact with said beveled edges, said semi-cylindricalmovable contact engagement with said Wedge shaped stationary contactseffective to cause high contact pressure engagement therebetween. saidsemi-cylindrical movable contact having rotational and linear movementwith respect to said pair of bus terminals, said linear movement of saidsemicylindrical movable contacts being perpendicular to the plane ofsaid bus terminals.

9. A short circuiting switch comprising a pair of co operating contactsfor opening and closing an electrical circuit, said cooperating contactscomprising a semi-cylindrical movable contactand a pair of bus terminalshaving beveled edges forming stationary contacts, said beveled surfacesof said pair of bus terminals forming a wedge shape to receive saidsemi-cylindrical bridging contact, said bridging contact makingtangential line contact with said beveled edges, resilient means to biassaid semicylindn'cal movable contact into engagement with saidstationary contacts, said resilient means exerting a biasing force onsaid semi-cylindrical movable contact in a direction perpendicular tothe plane of said pair of bus terminals, said wedge shaped engagement ofsaid movable contact with said stationary contacts causing said biasingforce of said resilient means on said movable contact to be resolvedinto two forces of greater magnitude to thereby achieve high contactpressure.

10. A short circuiting switch comprising a pair of cooperating contactsfor opening and closing an electrical circuit, said cooperating contactscomprising a semicylindrical movable contact and a pair of bus terminalshaving beveled edges forming stationary contacts, said beveled surfacesof said pair of bus terminals forming a wedge shape to receive saidsemi-cylindrical bridging contact, said bridging contact makingtangential line contact with said beveled edges, resilient means to biassaid semi-cylindrical movable contact into engagement with saidstationary contacts, said resilient means exerting a biasing force onsaid semi-cylindrical movable contact in a direction perpendicular tothe plane of said pair of bus terminals, said wedge shaped engagement ofsaid movable contact with said stationary contactscausing said biasingforce of said resilient means on said movable contact to be resolvedinto forces perpendicular to said beveled edges, said last mentionedforces being of greater magnitude than said biasing force of saidresilient means to thereby effect high contact pressure engagement withrelatively small biasing force.

11. A disconnect switch comprising a plurality of operating contacts forcompleting and interrupting an electrical :circuit between apair of busbar terminals, rotatable operating means comprising a shaft having aplurality of integrally connected cams, a-phirality of semi-cylindricalbridging contact members,.n'movingcontact lever secured to each of saidsemi-cylindrical bridging contacts, said moving contact levers rotatablyattached to said plurality of cams, compression springs concentric witheach of said moving contact levers and positioned between saidsemicylindrical bridging contacts and said cams, said operating meanstransmitting force to said semi-cylindrical movable contact through saidcompression spring.

12. A disconnect switch comprising a plurality of operating contacts forcompleting and interrupting an electrical circuit between a pair of busbar terminals, rotat able operating means comprising a shaft having aplurality of integrally connected cams, a plurality of sernicylindricalbridging contact members, a moving contact lever secured to each of saidsemi-cylindrical bridging contacts, said moving contact levers rotatablyattached to said plurality of cams, compression springs concen tric witheach of said moving contact levers and positioned between saidsemi-cylindrical bridging contacts and said cams, said operating meanstransmitting force to said semi-cylindrical movable contact through saidcompression spring, said rotatable engagement between said movablecontact levers and said plurality of cams permitting saidsemi-cylindrical movable contact to rotate into bridging positionbetween said stationary contacts, said rotational engagement of saidmovable contact with said stationary contact causing a wiping actiontherebetween, said compression spring causing said wiping action tooccur under pressure.

13. A disconnect switch comprising a plurality of operating contacts forcompleting and interrupting an electrical circuit between a pair of busbar terminals, rotatable operating means comprising a shaft having aplurality of integrally connected cams, a plurality of semicylindricalbridging contact members, a moving contact lever secured to each of saidsemi-cylindrical bridging contacts, said moving contact levers rotatablyattached to said plurality of cams, compression springs concentric witheach of said moving contact levers and positioned between saidsemi-cylindrical bridging contacts and said cams, said operating meanstransmitting force to said semicylindrical movable contact through saidcompression spring, said compression springs individual to each of saidsemi-cylindrical movable contacts permitting same to engage and seatwith said stationary contacts independently and individually of eachother.

14. A disconnect switch comprising a plurality of operating contacts forcompleting and interrupting an electrical circuit between a pair of busbar terminals, rotatable operating means comprising a shaft having aplurality of integrally connected earns, a plurality of semicylindricalbridging contact members, a moving contact lever secured to each of saidsemi-cylindrical bridging contacts, said moving contact levers rotatablyattached to said plurality of cams, compression springs concentric witheach of said moving contact levers and positioned between saidsemi-cylindrical bridging contacts and said cams, said operating meanstransmitting force to said semi-cylindrical movable contact through saidcompression spring, one of said movable contacts positioned below saidother movable contacts when said disconnect switch is in circuitinterrupting position, said one movable contact engaging said stationarycontacts before said other movable contacts, said one contactdisengaging said stationary contacts after disengagement of said othermovable contacts with said stationary contacts to thereby act as anarcing contact.

References Cited in the file of this patent UNITED STATES PATENTS1,531,917 French Mar. 31, 1925 2,529,662 Pipponzi Nov. 14, 19502,555,025 Cheek May 29, 1951 2,557,493 Andis June 19, 1951

